Embodiments of the present invention relate generally to image inspection systems and methods, and more particularly to an X-ray inspection system using tomosynthesis imaging techniques.
An image system may be used to inspect assemblies such as printed circuit boards (PCBs). PCBs may have connectors such as ball grid arrays (BGA) or column grid arrays (CGA). Examples of such connectors include the NeXLev® high-density parallel board connectors commercially available from Amphenol Corp. of Wallingford, Conn. These connectors are increasingly being used in PCB applications because they allow electronic design engineers to relocate high pin count devices onto a mezzanine or module card to simplify board routing without compromising system performance. Currently, there are about fourteen different types of high-density parallel board (i.e., NeXLev®-like) connectors in the PCB industry.
A PCB on which a BGA is present may be inspected for defects. Pins on a BGA may be deemed defective when solder does not reflow properly (or correctly) during manufacturing and/or where the solder reflow process is similarly deficient or otherwise insufficient. As a result, defects such as bridges and ball-and-socket-type opens may be present. The presence of such defects at or on any one pin will generally result in the failure of an entire connector on a multi-connector board.
The inspection of high-density parallel board connectors, such as the NeXLev® connectors, may involve several difficulties. At least some of these difficulties are related to: the impacts of the reflow process on the connectors; obscuration and associated artifacts produced by the connector blade; often subtle differences between non-defective (or acceptable) and defective (or unacceptable) solder balls; and the staggered positioning of solder balls in some BGAs.